/Engine/Source/Runtime/Engine/Classes/Animation/AnimClassInterface.h
Get the root anim class interface (i.e. if this is a derived class). Some properties that are derived from the compiled anim graph are routed to the 'Root' class as child classes don't get fully compiled. Instead they just override various asset players leaving the full compilation up to the base class.
const [IAnimClassInterface](API\Runtime\Engine\Animation\IAnimClassInterface) * GetRootClass() const